Breastfeeding is not only healthy for babies, it may also reduce a mother’s risk of having a heart attack or stroke later in life.

This is the conclusion of a new study of 300,000 Chinese women published Wednesday in the Journal of the American Heart Association..

According to Xinhua, the Chinese news agency, women who breastfed their babies had about a 10 percent lower risk of developing heart disease or stroke compared to those who did not.

The study said the longer mothers breastfeed, the greater effects they had.

“The findings should encourage more widespread breastfeeding for the benefit of the mother as well as the child,” study co-author Zhengming Chen, a professor of epidemiology at the University of Oxford, said in a statement.

“The study provides support for the World Health Organization’s recommendation that mothers should breastfeed their babies exclusively for their first six months of life,” Chen said.

Previous studies have suggested that mothers get short-term health benefits from breastfeeding, such as weight loss and lower cholesterol, blood pressure and glucose levels after pregnancy. However, the long-term effects of breastfeeding on the risk of developing cardiovascular diseases in mothers are unclear.

In the new study, researchers from the University of Oxford, the Chinese Academy of Medical Sciences and Peking University studied 300,000 Chinese women aged 30 to 79 years, as part of a large prospective cohort study called the China Kadoorie Biobank, which provided detailed information about their reproductive history and other lifestyle factors.

After eight years of follow-up, there were 16,671 cases of coronary heart disease which includes heart attacks, and 23,983 stroke cases among the 290,000 women who had no previous history of cardiovascular disease when enrolled in the study.

The researchers found that compared to women who had never breastfed, mothers who breastfed their babies had a nine percent lower risk of heart disease and an eight percent lower risk of stroke.

Among mothers who breastfed each of their babies for two years or more, heart disease risk was 18 percent lower and stroke risk was 17 percent lower than among mothers who never breastfed.

Each additional six months of breastfeeding per baby was associated with a four percent lower risk of heart disease and a three percent lower risk of stroke, the researchers said.

“Although we cannot establish the casual effects, the health benefits to the mother from breastfeeding may be explained by a faster ‘reset’ of the mother’s metabolism after pregnancy,” said study co-author Sanne Peters, research fellow at the University of Oxford.

“Pregnancy changes a woman’s metabolism dramatically as she stores fat to provide the energy necessary for her baby’s growth and for breastfeeding once the baby is born. Breastfeeding could eliminate the stored fat faster and more completely,” Peters added.